ISRO Scientist or Engineer Computer Science Dec 2017
For the following questions answer them individually
Consider the schema
Sailors(sid, sname, rating, age) with the following data
For the query
SELECT S.rating, AVG(S.age) AS avgage FROM Sailors S
Where S.age $$\ge$$ 18
GROUP BY S.rating
HAVING 1 $$<$$ (SELECT COUNT($$*$$) FROM Sailors S2 where S.rating $$=$$ S2.rating)
The number of rows returned is
Consider a table that describes the customers :
Customers(custid, name, gender, rating)
The rating value is an integer in the range 1 to 5 and only two values (male and female) are recorded for gender. Consider the query “how many male customers have a rating of 5”? The best indexing mechanism appropriate for the query is
Consider the following schema :
Sailors(sid,sname,rating,age)
Boats(bid,bname, colour)
Reserves(sid,bid,day)
Two boats can have the same name but the colour differentiates them.
The two relations
$$\rho(Tempsids, (\pi_{sid, bid}Reserves)/(\pi_{bid }(\sigma_{bname = 'Ganga'} Boats)))$$,
$$\pi_{sname}(Tempsids \bowtie Sailors)$$
If / is division operation, the above set of relations represents the query
Consider the following table : Faculty(facName, dept, office, rank, dateHired)
(Assume that no faculty member within a single department has same name. Each faculty member has only one office identified in office). 3NF refers to third normal form and BNCF
refers to Boyce-Codd normal form
Then Faculty is
Consider the following query :
SELECT E.eno, COUNT(*)
FROM Employees E
GROUP BY E.eno
If an index on eno is available, the query can be answered by scanning only the index if
If C is a skew-symmetric matrix of order n and X is $$n \times 1$$ column matrix, then $$X^T CX$$ is a
Consider the recurrence equation
$$T(n) = \begin{cases}2T(n - 1), & if n> 0\\1 & otherwise\end{cases}$$
Then T(n) is (in big O order)
Consider the program
void function (int n) {
int i, j, count = 0;
for (i = n/2; i <= n; i++)
for (j = 1; j <= n; j = j * 2)
count++;
}
The complexity of the program is
